Bone plate for elastic osteosynthesis

Abstract

Embodiments provide a method and device for plate osteosynthesis of a bone fracture that allows angle-stable fixation of the bone fracture, while permitting elastic axial motion at the fracture site in a controlled, symmetric manner to stimulate fracture healing. Embodiments pertain to a bone plate having an outer surface and a bone-facing surface. The bone plate incorporating internal sliding elements containing a threaded receiving hole for bone screws that have a correspondingly threaded screw head. The sliding elements undergo controlled displacement parallel to the longitudinal axis of the plate but are substantially constrained against displacement perpendicular to the longitudinal axis of the plate. The bone screws with threaded heads may be rigidly fixed to the threaded receiving holes in the sliding elements without compressing the bone plate onto the bone surface. Sliding elements are elastically suspended inside the bone plate and undergo dynamic motion.

What is claimed is: 
     
       1. A device, comprising:
 a bone fracture fixation plate having an outer surface, a bone-facing surface, a first end, a second end, and a longitudinal axis extending between the first and second ends, wherein the bone plate comprises one or more sliding elements elastically suspended relative to the bone plate, the elastic suspension of each sliding element in the plate being achieved by an elastic material disposed between the sliding element and the plate, each sliding element containing one or more threaded receiving holes for bone screws that have a correspondingly threaded head lockable at a fixed angle into the receiving holes; 
 wherein the one or more sliding elements undergo controlled displacement parallel to the longitudinal axis of the plate but are substantially constrained against displacement perpendicular to the longitudinal axis of the plate, and 
 wherein the one or more sliding elements are configured for rigid fixation to the bone screws without compressing the bone plate or sliding elements onto a bone surface. 
 
     
     
       2. The device of  claim 1 , wherein the elastic suspension of the sliding element is configured to effect an amount of bi-directional translation of the sliding element relative to the plate in response to an applied force in a longitudinal direction of the plate. 
     
     
       3. The device of  claim 2 , wherein the elastic material holds each sliding element in a defined resting position, and wherein compressibility of the elastic material determines an amount of uni-directional translation of each sliding element relative to the plate in response to an applied force in a longitudinal direction of the plate. 
     
     
       4. The device of  claim 1 , wherein the elastic material is a polymer. 
     
     
       5. The device of  claim 1 , wherein at least one of the sliding elements is partially or fully embedded in the elastic material to reduce friction between the sliding element and the plate. 
     
     
       6. The device of  claim 1 , wherein the one or more sliding elements are arranged in a staggered pattern within the plate to enhance rotational stability of the plate by limiting motion in a direction perpendicular to the longitudinal access. 
     
     
       7. The de vice of  claim 1 , wherein the plate further comprises non-threaded screw holes. 
     
     
       8. The device of  claim 1 , wherein the sliding elements are located in a first segment of the plate, and wherein a second segment of the plate comprises threaded or non-threaded holes without sliding elements. 
     
     
       9. The device of  claim 1 , further comprising a plurality of bone screws. 
     
     
       10. The device of  claim 1 , further comprising one or more non-collinear bone pegs having a threaded head and a non-threaded peg shaft. 
     
     
       11. The device of  claim 1 , wherein the receiving hole in the sliding element is conical. 
     
     
       12. The device of  claim 1 , wherein the receiving hole in the sliding element is cylindrical. 
     
     
       13. The device of  claim 1 , wherein the elastic material may positively adhere to at least a portion of the plate or sliding element surface to elastically constrain the sliding element relative to the bone plate. 
     
     
       14. The device of  claim 1 , wherein the elastic material comprises an elastomer lumen substantially free of voids. 
     
     
       15. The device of  claim 1 , wherein the elastic material comprises an elastomer lumen containing voids to increase the compressibility of the elastomer lumen. 
     
     
       16. The device of  claim 1 , wherein the elastic material has a modulus of elasticity in the range of 0.1-50 MPa. 
     
     
       17. The device of  claim 1 , wherein the elastic modulus and formulation of the elastic material may vary within the elastic material. 
     
     
       18. The device of  claim 1 , wherein the sliding element is removable as a solitary element or is assembled to the elastic material prior to assembly into the plate. 
     
     
       19. The device of  claim 1 , wherein one or more sliding elements extend past the bone-facing surface of the plate to elevate the plate body over the bone surface when the receiving hole is being compressed onto the bone surface with a non-locking bone screw, which, in conjunction with the elastic suspension of the sliding element, enables controlled motion between the plate and the bone surface. 
     
     
       20. The device of  claim 1 , wherein the elastic material is silicone. 
     
     
       21. The device of  claim 1 , wherein the sliding element is at least partially enclosed within a cavity in a side of the plate. 
     
     
       22. A device, comprising:
 a bone fracture fixation plate having an outer surface and a bone-facing surface, wherein the bone plate comprises one or more sliding elements elastically suspended relative to the bone plate, wherein each sliding element contains one or more threaded receiving holes for bone screws that have a correspondingly threaded head lockable at a fixed angle into the receiving holes; 
 wherein the elastic suspension of the sliding element in the plate is achieved by two or more spring elements formed by an elastic material applied between the sliding element and the plate, wherein the spring elements effect an amount of bi-directional translation of the sliding element relative to the plate in response to an applied force in a longitudinal direction of the plate; 
 wherein the one or more sliding elements undergo controlled displacement parallel to a longitudinal axis of the plate but are substantially constrained against displacement perpendicular to the longitudinal axis of the plate; and 
 wherein the one or more sliding elements are configured for rigid fixation to the bone screws without compressing the bone plate or sliding elements onto a bone surface. 
 
     
     
       23. A device, comprising:
 a bone fracture fixation plate having an outer surface and a bone-facing surface, wherein the bone plate comprises one or more sliding elements elastically suspended relative to the bone plate, wherein each sliding element contains one or more threaded receiving holes for bone screws that have a correspondingly threaded head lockable at a fixed angle into the receiving holes; 
 wherein the one or more sliding elements undergo controlled displacement parallel to a longitudinal axis of the plate but are substantially constrained against displacement perpendicular to the longitudinal axis of the plate; 
 wherein the one or more sliding elements are configured for rigid fixation to the bone screws without compressing the bone plate or sliding elements onto a bone surface; and 
 wherein the one or more sliding elements extend past the bone-facing surface of the plate to elevate the plate body over the bone surface when the receiving hole is being compressed onto the bone surface with a non-locking bone screw, which, in conjunction with the elastic suspension of the sliding element, enables controlled motion between the plate and the bone surface.